1. Technical Field
The present invention relates to a system, a program and a method for retrieving an image adapted for a retrieving key image from plural images, or classifying the plural images. In particular, the present invention relates to an image retrieving system, an image classifying system, an image retrieving program, an image classifying program, an image retrieving method and an image classifying method suitable for acquiring a retrieving result or a classifying result satisfying the desire of a user.
2. Related Art
JP-A-2001-52175 discloses a conventional technique for retrieving an image similar to the retrieving key image from plural retrieving object images on the basis of the given retrieving key image. The image retrieving device described in JP-A-2001-52175 has a characteristic vector extracting section, a reference vector group processing section, a similar degree calculating section, a similar degree judging section and a taking-out section. The characteristic vector extracting section extracts plural characteristic amounts from acquired object image data or reference image data and generates a characteristic vector. The reference vector group processing section makes a reference vector and generates a reference vector group by integrating the characteristic vector extracted in the characteristic vector extracting section and address information of this reference image for each reference image data with respect to the plural acquired reference image data. The similar degree calculating section calculates similar degrees of the characteristic vector extracted in the characteristic vector extracting section from the acquired object image data, and the characteristic vector of the reference image data selected from the reference vector group. The similar degree judging section compares the calculated similar degree with a predetermined standard. The taking-out section takes-out the address information of an image judged as a similar image from the reference vector group.
Here, a color, texture, structural characteristics, or time-like characteristics are used as characteristic amounts of the image. The characteristic amounts are calculated by calculating a density histogram, a simultaneous normal matrix, a differential statistical amount, etc. with respect to the texture, and are also calculated by the convolution of a Laplacian filter, Hough transform, etc. with respect to the structural characteristics of an edge, a line, a contour, etc. The characteristic amounts are also calculated by an RGB space, an HSV space, or conversion into a spectrum, etc. with respect to the color, and are also calculated by the calculation of an optical flow and conversion into a wavelet with respect to the time-like characteristics.
The concept of similarity greatly depends on the subjectivity of a human being. Accordingly, there is a case in which a certain person has a feeling of similarity with respect to-an image, but another person has a feeling of non-similarity with respect to this image. Therefore, when the similarity of the image is retrieved, how to define the concept of the similarity is important.
If the entire image and a portion of the image are considered, for example, an image similar as a whole but not similar with respect to a characteristic portion, and an image reversely similar with respect to the characteristic portion but not similar as a whole exist with respect to the retrieving key image. However, it is necessary to appropriately evaluate the similar degree with respect to each of these images. When a user sees the image, the user notices the characteristic portion (a flower portion if it is an image formed by mainly photographing a flower) within the image. Therefore, the user ought to have a feeling in which the image similar with respect to the characteristic portion but not similar as a whole is more similar in comparison with the image similar as a whole but not similar with respect to the characteristic portion. Accordingly, the method for evaluating the similar degree of the image by seriously considering the similar degree with respect to the characteristic portion within the image and lightly considering the similar degree with respect to an uncharacteristic portion is suitable for the actual situation in comparison with the method for evaluating the similarity by gripping the entire image.
However, in the image retrieving device described in JP-A-2001-52175, the characteristic vector is generated by extracting plural characteristic amounts from the entire image data, and the similarity of the image is retrieved on the basis of the generated characteristic vector. Therefore, no similar degree of the image is evaluated in consideration of a portion noticed by the user. Accordingly, a problem exists in that no subjectivity of the user can be sufficiently reflected in the retrieving result, and no retrieving result according to the desire of the user is obtained.
This problem is not limited to the retrieving case of the similarity of the image, but a similar problem is also supposed with respect to a case in which plural images are classified in accordance with their similar degrees. Therefore, the present invention is made by focusing on such an unsolved problem in the prior art, and an object of the present invention is to provide an image retrieving system, an image classifying system, an image retrieving program, an image classifying program, an image retrieving method and an image classifying method suitable for acquiring a retrieving result or a classifying result according to the desire of the user.